Enhanced Motion Aftereffects in Migraine Are Related to Contrast Sensitivity: Implications for Models of Differences in Precortical/Cortical Function.

Abstract

Visual tests can be used as noninvasive tools to test models of the pathophysiology underlying neurological conditions, such as migraine. For example, there are reports that the motion aftereffect, which involves neural processing in several cortical areas, is prolonged in migraine. There also are reports of impaired contrast sensitivity in migraine, however, attributed to a precortical dysfunction. This study explored associations between these two tests of visual function. Specifically, it aimed to clarify whether the magnitude of the motion aftereffect is affected by contrast and contrast sensitivity. The motion aftereffect was elicited after observers viewed a coherently moving pattern for 45 seconds. The duration of the subsequent aftereffect was measured with three different test display contrasts (high, medium, low). Contrast sensitivity also was assessed. For each test display contrast, the motion aftereffect was prolonged in migraine compared to the control group. Contrast sensitivity was poorer in the migraine group and was a significant predictor of motion aftereffect duration. These results suggest an anomaly in early motion processing pathways in migraine that likely is linked with those pathways underlying contrast sensitivity. They provide further evidence for differences in visual processing that begin early, potentially starting at the retina, which have consequences for performance on tasks that putatively examine cortical processing. Differences in precortical and cortical visual pathways are implicated in the pathophysiology underlying migraine.